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A method for determination of aromatics in 150 degree to 300 degree C fractions of crude petroleum by measurement of aniline-point rise

Description: Report presenting a method for determining aromatics in several fractions of crude petroleum. A general curve for analysis of cuts of crude petroleum with molal average boiling points near 218 degrees Celsius is presented.
Date: June 1948
Creator: Busch, Arthur M.; Cleaves, Alden P. & Hibbard, Robert R.
Partner: UNT Libraries Government Documents Department

Knock-Limited Blending Characteristics of Benzene, Toluene, Mixed Xylenes, and Cumene in an Air-Cooled Cylinder

Description: "An investigation was conducted to determine the knock-limited blending characteristics of leaded fuels containing selected aromatic fuel components (benzene, toluene, mixed xylenes, and cumene). Each of the aromatics was blended with an alkylate blending agent and with a virgin base stock. The blending characteristics of the resulting fuels were determined in a full-scale aircraft-engine cylinder" (p. 1).
Date: February 3, 1945
Creator: Hensley, Reece V. & Breitwieser, Roland
Partner: UNT Libraries Government Documents Department

Simultaneously Bound Guests and Chiral Recognition: A Chiral Self-Assembled Supramolecular Host Encapsulates Hydrophobic Guests

Description: Driven by the hydrophobic effect, a water-soluble, chiral, self-assembled supramolecular host is able to encapsulate hydrophobic organic guests in aqueous solution. Small aromatics can be encapsulated in the supramolecular assembly, and the simultaneous encapsulation of multiple guests is observed in many cases. The molecular host assembly is able to recognize different substitutional isomers of disubstituted benzenes with ortho substitution leading to the encapsulation of two guests, but meta or para substitution leading to the encapsulation of only one guest. The scope of hydrophobic guest encapsulation is further explored with chiral natural product guests. Upon encapsulation of chiral guests into the racemic host, diastereomeric host-guest complexes are formed with observed diastereoselectivities of up to 78:22 in the case of fenchone.
Date: March 6, 2008
Creator: Hastings, Courtney J.; Pluth, Michael D.; Biros, Shannon M.; Bergman, Robert G. & Raymond, Kenneth N.
Partner: UNT Libraries Government Documents Department

Asymmetric Intramolecular Alkylation of Chiral Aromatic Imines via Catalytic C-H Bond Activation

Description: The asymmetric intramolecular alkylation of chiral aromatic aldimines, in which differentially substituted alkenes are tethered meta to the imine, was investigated. High enantioselectivities were obtained for imines prepared from aminoindane derivatives, which function as directing groups for the rhodium-catalyzed C-H bond activation. Initial demonstration of catalytic asymmetric intramolecular alkylation also was achieved by employing a sterically hindered achiral imine substrate and catalytic amounts of a chiral amine.
Date: April 16, 2007
Creator: Watzke, Anja; Wilson, Rebecca; O'Malley, Steven; Bergman, Robert & Ellman, Jonathan
Partner: UNT Libraries Government Documents Department

Enantioselective Intramolecular Hydroarylation of Alkenes via Directed C-H Bond Activation

Description: Highly enantioselective catalytic intramolecular ortho-alkylation of aromatic imines containing alkenyl groups tethered at the meta position relative to the imine directing group has been achieved using [RhCl(coe){sub 2}]{sub 2} and chiral phosphoramidite ligands. Cyclization of substrates containing 1,1- and 1,2-disubstituted as well as trisubstituted alkenes were achieved with enantioselectivities >90% ee for each substrate class. Cyclization of substrates with Z-alkene isomers proceeded much more efficiently than substrates with E-alkene isomers. This further enabled the highly stereoselective intramolecular alkylation of certain substrates containing Z/E-alkene mixtures via a Rh-catalyzed alkene isomerization with preferential cyclization of the Z-isomer.
Date: May 22, 2008
Creator: Harada, Hitoshi; Thalji, Reema; Bergman, Robert & Ellman, Jonathan
Partner: UNT Libraries Government Documents Department

An atomic force microcopy study of the mechanical and electricalproperties of monolayer films of molecules with aromatic end groups

Description: The effect of intermolecular {pi}-{pi} stacking on the electrical and mechanical properties of monolayer films molecules containing aromatic groups was studied using atomic force microscopy. Two types of aromatic molecules, (4-mercaptophenyl) anthrylacetylene (MPAA) and (4-mercaptophenyl)-phenylacetylene (MPPA) were used as model systems with different {pi}-{pi} stacking strength. Monolayer films of these molecules on Au(111) surfaces exhibited conductivities differing by more than one order of magnitude, MPAA being the most conductive and MPPA the least conductive. The response to compressive loads by the AFM tip was also found to be very different for both molecules. In MPAA films distinct molecular conductivity changes are observed upon mechanical perturbation. This effect however was not observed on the MPPA film, where intermolecular {pi}-{pi} interactions are likely weaker.
Date: September 6, 2007
Creator: Fang, Liang; Park, J.Y.; Ma, H.; Jen, A.K.-Y. & Salmeron, M.
Partner: UNT Libraries Government Documents Department


Description: "Ultrasene" typically contained 57 wt % branched paraffins and cycloparaffins, 40 wt% n-paraffins, 3 wt% aromatics, and less than 0.1 wt% olefins. The n-paraffinic fraction from "Ultrasene" was stable to chemical and radiolytic degradation, whereas the combined branched paraffinic and cycloparaffinic fraction, and the aromatic fraction, were significantly less stable. (auth)
Date: June 1, 1961
Creator: West, D. L.
Partner: UNT Libraries Government Documents Department

High Conversion of Coal to Transportation Fuels for the Future With Low HC Gas Production

Description: An announced objective of the Department of Energy in funding this work, and other current research in coal liquefaction, is to produce a synthetic crude from coal at a cost lower than $30.00 per barrel (Task A). A second objective, reflecting a recent change in direction in the synthetic fuels effort of DOE, is to produce a fuel which is low in aromatics, yet of sufficiently high octane number for use in the gasoline- burning transportation vehicles of today. To meet this second objective, research was proposed, and funding awarded, for conversion of the highly-aromatic liquid product from coal conversion to a product high in isoparaffins, which compounds in the gasoline range exhibit a high octane number (Task B).
Date: July 1, 1996
Creator: Oblad, Alex G. & Wiser, Wendell H.
Partner: UNT Libraries Government Documents Department

The Efficacy of Oxidative Coupling for Promoting In-Situ Immobilization of Hydroxylated Aromatics in Contaminated Soil and Sediments Systems - Final Report

Description: The study clearly shows that the structure and composition of the organic matter of soils and sediments are essential considerations for the selection of materials for engineered applications of oxidative coupling processes. A rate model was developed to facilitate quantitative evaluation and mechanistic interpretation of these fairly complex coupling processes.
Date: October 1, 2000
Creator: Weber Jr., W. J.
Partner: UNT Libraries Government Documents Department

Photoinduced electron transfer and fluorescence mechanisms in covalently linked polynuclear aromatic-nucleotide complexes

Description: The fluorescence of polycyclic aromatic hydrocarbon-nucleic acid complexes is quenched by photoinduced electron transfer mechanisms in aqueous solutions at ambient temperatures. These effects are illustrated with the biologically important compound benzo(a)pyrene-7,8-diol-9,10-epoxide (BPDE), a mutagenic and carcinogenic metabolite of the environmental pollutant benzo(a)pyrene, which forms covalent mutagenic lesions with 2{prime}-deoxyguanosine (dG) residues in DNA. The dependence of the fluroescence yeild and fluorescence decay times of the covalent model adduct (+)-trans-BPDE-N{sup 2}-dG as a function of temperature and methanol/water composition are described. Because of the sensitivity of the fluorescence of the pyrenyl residue to the polarity of the microenvironment, the magnitude of the fluorescence yield can be used to distinguish between highly hydrophobic (e.g. intercalation) and other more solvent-exposed BPDE-nucleic acid binding sites.
Date: January 1, 1992
Creator: Geacintov, N.E.; Mao, Bing; Zhao, Rushen; Chen, Junxin; Liu, Tong Ming; Ya, Nai-Qi (New York Univ., NY (United States). Dept. of Chemistry) et al.
Partner: UNT Libraries Government Documents Department

Spontaneous and stimulated Raman studies of vibrational dephasing in condensed phases

Description: Vibrational dephasing in condensed phases is studied from both a theoretical and experimental standpoint. A theory is presented which describes the dynamics of motional or exchange processes in weakly perturbed systems. This general formalism, which has been previously used to describe motional narrowing in magnetic resonance, is applied to vibrational spectroscopy. The model treats the case of a high frequency vibration anharmonically coupled to a low-frequency vibration. Intermolecular exchange of low frequency vibrational quanta results in a temperature dependent broadening and frequency shift of the high frequency vibration. Analysis of experimental data by this model yields both the exchange rates and the anharmonic couplings.
Date: May 1, 1980
Creator: Cornelius, P.A.
Partner: UNT Libraries Government Documents Department

Multiphoton ionization and excitation spectroscopy of molecules in liquids. [Fluoranthene]

Description: The two-photon ionization and excitation spectra of fluoranthene in liquid n-pentane have been measured and together with laser power versus signal intensity measurements have been utilized to elucidate the multiphoton ionization mechanism for this and other molecules in liquids.
Date: January 1, 1984
Creator: Siomos, K.; Faidas, H. & Christophorou, L.G.
Partner: UNT Libraries Government Documents Department

Gas and Particulate Sampling of Airborne Polycyclic Aromatic Compounds

Description: The denuder surfaces of the gas and particle (GAP) sampler (developed at the Atmospheric Environment Service of Environment Canada) have been modified by coating with XAD-4 resin, using techniques developed at Lawrence Berkeley National Laboratory (LBNL) for the lower capacity integrated organic vapor/particle sampler (IOVPS). The resulting high capacity integrated organic gas and particle sampler (IOGAPS) has been operated in ambient air at 16.7 L min{sup -1} for a 24-hour period in Berkeley, California, USA. Simultaneous measurements were made at the same collection rate with a conventional sampler that used a filter followed by two sorbent beds. Gas and particle partition measurements were determined for 13 polycyclic aromatic hydrocarbons (PAH) ranging from 2-ring to 6-ring species. The IOGAPS indicated a higher particle fraction of these compounds than did the conventional sampler, suggesting that the conventional sampler suffered from 'blow-off' losses from the particles collected on the filter.
Date: October 1, 1995
Creator: Lane, D.A. & Gundel, L.A.
Partner: UNT Libraries Government Documents Department

Graphene Layer Growth Chemistry: Five-Six-Ring Flip Reaction

Description: A theoretical study revealed a new reaction pathway, in which a fused five and six-membered ring complex on the zigzag edge of a graphene layer isomerizes to reverse its orientation, or 'flips,' after activation by a gaseous hydrogen atom. The process is initiated by hydrogen addition to or abstraction from the surface complex. The elementary steps of the migration pathway were analyzed using density-functional theory (DFT) calculations to examine the region of the potential energy surface associated with the pathway. The DFT calculations were performed on substrates modeled by the zigzag edges of tetracene and pentacene. Rate constants for the flip reaction were obtained by the solution of energy master equation utilizing the DFT energies, frequencies, and geometries. The results indicate that this reaction pathway is competitive with other pathways important to the edge evolution of aromatic species in high temperature environments.
Date: March 24, 2007
Creator: Whitesides, Russell; Domin, Dominik; Lester Jr., William A. & Frenklach, Michael
Partner: UNT Libraries Government Documents Department

Absorption Spectra of Aromatic Disulfides

Description: The effect of solvents and temperature on the optical absorption spectrum of a number of substituted aromatic disulfides is reported. The problems offered by the disulfide link and the exchange reactions between disulfides, and between disulfides and thiols, are receiving increasing attention. Recently the base-catalyzed exchange between various alkyl disulfides and the corresponding thiols was studied by means of a radioactive-tracer technique. Our initial purpose was to extend these investigations to a large number of compounds in a variety of experimental conditions using a spectrophotometric technique that, if applicable, would have been incomparably faster.
Date: October 31, 1956
Creator: Fava, Antonio & Calvin, Melvin
Partner: UNT Libraries Government Documents Department


Description: Using infra-red spectroscopy, the equilibrium exchange times have been determined for a series of ketones, aromatic aldehydes, and {beta}-ketoesters reacting with oxygen 18 enriched water. These exchange times have been evaluated in terms of steric and electronic considerations, and applied to a discussion of the exchange times of chlorophylls a and b and chlorophyll derivatives.
Date: December 1, 1965
Creator: Byrn, Marianne & Calvin, Melvin
Partner: UNT Libraries Government Documents Department

Heterocyclic Aromatic Amines in Domestically Prepared Chicken and Fish from Singapore Chinese Households

Description: Chicken and fish samples prepared by 42 Singapore Chinese in their homes were obtained. Researchers were present to collect data on raw meat weight, cooking time, maximum cooking surface temperature, and cooked meat weight. Each participant prepared one pan-fried fish sample and two pan-fried chicken samples, one marinated, one not marinated. The cooked samples were analyzed for five heterocyclic aromatic amine (HAA) mutagens, including MeIQx (2-amino 3,8-dimethylimidazo[4,5-f]quinoxaline); 4,8-DiMeIQx (2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline); 7,8-DiMeIQx (2-amino-3,7,8-trimethylimidazo[4,5-f]quinoxaline); PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine), and IFP (2-amino-(1,6-dimethylfuro[3,2-e]imidazo [4,5-b])pyridine). A paired Student's t-test showed that marinated chicken had lower concentrations of PhIP (p<0.05), but higher concentrations of MeIQx (p<0.05) and 4,8-DiMeIQx (p<0.001) than non-marinated chicken, and also that weight loss due to cooking was less in marinated chicken than in non-marinated chicken (p<0.001). Interestingly, the maximum cooking surface temperature was higher for fish than for either marinated or non-marinated chicken (P<0.001), yet fish was lower in 4,8-DiMeIQx per gram than marinated or non-marinated chicken (p<0.001), lower in PhIP than non-marinated chicken (P<0.05), and lost less weight due to cooking than either marinated or non-marinated chicken (P<0.001). Fish was also lower in MeIQx and 7,8-DiMeIQx than marinated chicken (P<0.05). This study provides new information on HAA content in the Singapore Chinese diet.
Date: May 16, 2005
Creator: Salmon, C P; Knize, M G; Felton, J S; Zhao, B & Seow, A
Partner: UNT Libraries Government Documents Department

Efficient Route to Highly Water-Soluble Aromatic Cyclic Hydroxamic Acid Ligands

Description: 2-Hydroxyisoquinolin-1-one (1,2-HOIQO) is a new member of the important class of aromatic cyclic hydroxamic acid ligands which are widely used in metal sequestering applications and metal chelating therapy. The first general approach for the introduction of substituents at the aromatic ring of the chelating moiety is presented. As a useful derivative, the highly water-soluble sulfonic acid has been synthesized by an efficient route that allows general access to 1,2-HOQIO 3-carboxlic acid amides, which are the most relevant for applications.
Date: February 6, 2008
Creator: Seitz, Michael & Raymond, Kenneth N.
Partner: UNT Libraries Government Documents Department

Stopping the growth of particles to silica-supported mono-nuclear Ru hydride surface species by tuning silica with surface silanes

Description: Tuning silica by replacing surface silanols with silanes allows chemical grafting of Ru(COD)(COT) through a covalent Ru-Si bond, as evidenced by elemental analysis, IR spectroscopy and EXAFS. Treatment of these surface species under H2 at 300 oC yields a mononuclear Ru hydride species, without any sintering of the metal according to TEM and EXAFS analyses. This supported system displays catalytic properties different from those of supported Ru particles (2 nm), selectively hydrogenating olefins over aromatics.
Date: July 11, 2007
Creator: Berthoud, Romain; Fenet, Bernard; Lukens, Wayne; Pelzer, Katrin; Basset, Jean-Marie; Candy, Jean-Pierre et al.
Partner: UNT Libraries Government Documents Department

Carbonyl Emissions from Gasoline and Diesel Motor Vehicles

Description: Carbonyls from gasoline powered light-duty vehicles (LDVs) and heavy-duty diesel powered vehicles (HDDVs) operated on chassis dynamometers were measured using an annular denuder-quartz filter-polyurethane foam sampler with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine derivatization and chromatography-mass spectrometry analyses. Two internal standards were utilized based on carbonyl recovery, 4-fluorobenzaldehyde for<C8 carbonyls and 6-fluoro-4-chromanone for>_C8 compounds. Gas- and particle-phase emissions for 39 aliphatic and 20 aromatic carbonyls ranged from 0.1 ? 2000 ?g/L fuel for LDVs and 1.8 - 27000 mu g/L fuel for HDDVs. Gas-phase species accounted for 81-95percent of the total carbonyls from LDVs and 86-88percent from HDDVs. Particulate carbonyls emitted from a HDDV under realistic driving conditions were similar to concentrations measured in a diesel particulate matter (PM) standard reference material. Carbonyls accounted for 19percent of particulate organic carbon (POC) emissions from low-emission LDVs and 37percent of POC emissions from three-way catalyst equipped LDVs. This identifies carbonyls as one of the largest classes of compounds in LDV PM emissions. The carbonyl fraction of HDDV POC was lower, 3.3-3.9percent depending upon operational conditions. Partitioning analysis indicates the carbonyls had not achieved equilibrium between the gas- and particle-phase under the dilution factors of 126-584 used in the current study.
Date: December 1, 2007
Creator: Destaillats, Hugo; Jakober, Chris A.; Robert, Michael A.; Riddle, Sarah G.; Destaillats, Hugo; Charles, M. Judith et al.
Partner: UNT Libraries Government Documents Department

1,2-HOIQO--A highly versatile 1,2-HOPO analog

Description: A cyclic, bidentate hydroxamic acid binding unit based on an isoquinoline scaffold has been utilized for the synthesis of a hexadentate tripodal ligand based on the TREN backbone. This prototype for a new class of multidentate chelators forms mononuclear iron(III) complexes and one-dimensional coordination polymers with lanthanide(III) cations. The latter has been determined by single crystal X-ray analysis of the cerium species. The solid state structure in the monoclinic space group P2{sub 1}/c (C{sub 36}H{sub 34}CeN{sub 7}O{sub 11}, a = 12.341(2){angstrom}, b = 26.649(4){angstrom}, c = 10.621(2){angstrom}, {alpha} = {gamma} = 90{sup o}, {beta} = 96.753(3){sup o}, V = 3468.6(9) {angstrom}{sup 3}, Z = 4) exhibits a trigonal-dodecahedral environment around the cerium cation. The proof of concept for the versatility of the new scaffold has been shown by the modification of the crucial precursor 3-carboxyiso-coumarin through electrophilic aromatic substitutions to yield the corresponding chlorosulfonated and nitrated analogs.
Date: August 7, 2006
Creator: Seitz, Michael; Pluth, Michael D. & Raymond, Kenneth N.
Partner: UNT Libraries Government Documents Department


Description: The C/sup 1//sup 1/-C/sup 1//sup 4/ components of a sample of"Ultrasene" were identified as normal- and iso-paraffins; mono-, bi-, and tri-cycloparaffins; alkylbenzenes; indans; indenes; naphthalenes; and acenaphthenes. The aromatic content of this sample was 3.0 vol%. (auth)
Date: April 1, 1961
Creator: Wilhite, R. N.
Partner: UNT Libraries Government Documents Department


Description: The tendency of various classes of pure hydrocarbons to form zirconium- complexing ligands during chemical or radiolytic degradation was evaluated. Olefins and aromaticcycloparaffins (mixed type) formed the most ligands and normal paraffins the fewest. (auth)
Date: April 1, 1961
Creator: Dennis, B.P.
Partner: UNT Libraries Government Documents Department